Electric switchgear



Oct. 13, 1942- B. w. MAHONEY ELECTRIC SWITCHGEAR Filed June 4, 1940 2 Sheets-Sheet l Inventor Ber'tram W. Mahone fim b 5 His Attorney.

Oct. 13, 1942. 5, w MAHONEY 2,298,828

ELECTRIC SWITCHGEAR 2 Sheets-Sheet 2 Inventor: Ber-cram W. Mahoney,

His Attorney.

. stationary metal housing Patented Oct. 13, 1942 2,298,828 ELECTRIC SWITCHGEAR Drexel Hill, Pa., asaignor ompany, a corporation of Bertram W. Mahoney,

to General Electric New York Application June 4, 1940, Serial No. 338,750 6 Claims. (01. 115-298) My invention relates to electric switchgear and more particularly to metal-enclosed switchgear of the draw-out type. a

In metal-enclosed switchgear 01 the draw-out type, the conventional arrangement comprises a within which bus bars, cable leads, and accessory apparatus are disposed and a removable unit comprising a circuit breaker which is suitably connected to the busses and incoming or outgoing leads in the operative position of the unit. In this position, so-called primary disconnecting contacts comprising contacts connected to the busses and incoming or outgoing leads and fixedly mounted with respect to the stationary housing and coacting movable contacts carried by the removable unit are in engagement. The apparatus is also provided with suitable interlocking means generally arranged so that it is impossible to insert or withdraw the removable unit or break connection at the primary disconnecting contacts without first tripping the circuit breaker, and insuring that the circuit breaker is open both when the unit is moved out of and into operative position. Switchgear of the draw-out type is usually adapted to assume a plurality of positions in the metal-enclosed housing, one of which is a test position when the primary disconnecting contacts are disengaged and another a circuit-controlling position when the primary disconnecting contacts are engaged. In the former position, the operation of the circuit breaker may be tested.

In order to obtain proper engagement of the primary disconnecting contacts, it is essential in draw-out type switchgear that the movable and stationary parts of such contacts are properly aligned as the removable unit including the circuit breaker moves into position. This has heretofore necessitated the accurate alignment of the movable structure with respect to the stationary structure, the obtaining of which required accurate or precision machining which was very costly. Inasmuch as the metal enclosure and the removable unit are relatively large structures and ordinarily constructed somewhat roughly as compared with more delicate electrical devices, it was necessary heretofore to make adjustments on the primary disconnecting contacts when assembling the apparatus so that they would be in proper alignment. Furthermore, it a rack-out mechanism were provided, adjustments to such mechanism were also necessary in order that the parts associated with the metal enclosure and the movable unit would necessary available.

In order to overcome such diillculties, various arrangements have been proposed, such as providing floating contacts for the disconnecting devices which would be self-aligning. However, all such proposals considerably complicate the apparatus and add to the cost thereof so as to be more or less unsatisfactory. It would be desirable to provide metal-enclosed switchgear of the draw-out type in which all adjustments of the primary disconnecting devices including the stationary portions thereof and the cooperating parts of the rack-out mechanism, if one is provided, could be made outside of the metalenclosed housing.

Accordingly, it is an object of my invention to provide an improved metal-enclosed switchgear of the draw-out type, overcoming the disadvantages noted in connection with prior art devices, which is simple and rugged in construction and eilicient and safe in operation.

It is another object of my invention to provide a new and improved metal-enclosed switchgear of the draw-out type in which all adjustments for aligning the contacts of the primary disconnecting devices including the stationary part thereof may be made prior to installation in the metal-enclosed unit. a

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to the accompanying drawings in which Fig. l is a side elevation partly in section of a metal-enclosed switchgear including a plurality of units embodying my invention, Fig. 2 is an elevational view of the removable unit including the circuit breaker, Fig. 3 is a side elevation of an intermediate unit of my improved metal-enclosed electric switchgear including the stationary part of the primary disconnecting devices, Fig. 4 is a front elevational view of one unit of my metal-enclosed switchgear, Fig. 5 is a view taken on line 8-5 of Fig.

4, and Fig. 6 is a view taken on line 6-5 of Fig. 4.

Referring now to the drawings, 1 have illustrated in Fig. 1 a stationary housing it arranged no is shown in the circuit-controlling position while the removable unit 62 for the upper section of housing in is shown just prior to being inserted in the metal enclosure in which it would engage with intermediate unit it so as to be horizontally movable into and out of housing to. Each of the sections of housing it within which the switching units are mounted is pro- Vltled with a suitable door M.

For the purposes of clearness and simplicity in the drawings, the bus bars, cable leads, feeders, and accessory apparatus are omittedfrom the stationary housing it. The intermediate units H support the stationary portions i5 of the primary disconnecting devices and are suitably mounted in housing ill on angle irons l6 horizontally positioned along the side walls thereof. Preferably, intermediate units H are attached to these angle irons as by bolts l6 and may also be fastened to the back of housing was by bolts I6". I have illustrated these intermediate units H as comprising a vertical portion i1 and a horizontal platform i8 suitably fastened together as by welding. Vertical portion ll supports'the stationary portion it of ing devices and may comprise a suitable vertically positioned insulating member is the stationary connecting devices extend. Platform I8 is provided with a depending flange H8 at the front thereof which engages with angle irons it, as shown best in Figs. 1 and 4, to determine the position of intermediate unit ii in housing in. On either side of platform 98 is provided a row of antifriction devices such as ball bearings suitably mounted and arranged in a horizontal plane so that removable unit if may be slidably supported thereon.

The removable unit 92 of the switchgear is horizontally movable and includes a channel shaped member 2! and a pair of depending angleiron supports 24, the latter arranged to slidably engage with ball bearings 20 so that removable unit l2 may be inserted or withdrawn in drawer fashion from housing ill. In order to prevent vertical movement of removable unit it relative to intermediate unit it and horizontal movement other than in a direction into and out of housing W as well as to hold angle-iron supports in engagement with ball bearings 20, I provide a single, central, horizontal dovetail guide comprising member 22 suitably fastened to platform E8 of intermediate unit H and cooperating member 23 suitably fastened to removable unit l2. The end of cooperatingmember 23 adjacent the rear of housing ill, as shown in Fig. 5, is suitably rounded at 23 to facilitate engagement with member 22 of intermediate unit it when removable unit i2 is moved toward inthrough which portions E5 of the primary disthe primary disconnecttermediate unit ii. .By this arrangement, unit 98 is readily movable in a horizontal plane away from and toward intermediate unit ii. A suitable handle 25 is attached by any suitable means unit ll. While the stationary portions 15 of the primary disconnecting contacts are illustrated as of the male type adapted to engage with the spring-pressed jaws of female type contact 26 associated with the removable unit 12, it will, of course, be understood by those skilled in the art that contacts i5 and 26 making up the primary disconnecting devices may be constructed in any other suitable manner and the particular embodiment shown is only one of the many arrangements possible. 'Ii'he secondary or control connections for electrically operating the circuit breaker 53 are not shown but it will be understood by those skilled in the art that these connections are completed so that operation of the circuit breaker may be obtained in the test as well as in the operative position, as will be described in greater detail hereinafter.

Because of the resistance encountered between the cooperating contact members 55 and 26 of the primary disconnecting devices upon engagement or disengagement thereof, it may be desirable to provide a rack-out mechanism or force-multiplying means between intermediate unit it and removable unit 82. Such a rack-out mechanism is not shown in the drawing since it forms no part of the present invention but, in my copending application, Serial No. 321,709, filed March 1, 1940, and assigned to the same assignee as the present invention, there is disclosed and claimed a suitable rack-out mechanism which may be applied to the metal-enclosed switchgear of the draw-out type of the present invention.

The removable unit i2 is also provided with a locking device to prevent it from being rolled in or out beyond the proper limits and also to hold it in a plurality of positions, such as the test position, wherein the primary disconnecting contacts are disengaged so that'the operation of the circuit breaker may be tested or the circuitcontrolling position where the primary disconnecting contacts are engaged. This locking device, best shown in Figs. 4, 5, and 6, comprises a lever El pivotally mounted at 28 to removable unit i2 and provided with a manually operable catch lever 29 at one end thereof adjacent handie 25. Lever 21 is arranged to be connected by means of link 39 with lever iii pivotally mounted to the roll-out unit at 32. The free end of lever 35 is provided with a pin 33 perpendicularly 81, the removable and whenit projects into opening 3|, the roll-out shelf II is in its withdrawn position.

- Aswillbeunderstoodbythoseskilledintheart, it is necessary to provide metal-enclosed switchgear of the draw-out type with suitable interlocking means so that it is impossible to insert or withdraw the removable unit or break connection at the primary disconnecting contacts without first tripping the circuit breaker and, furthermore, insuring that the circuit breaker is open both when the unit is moved out of and into operative position. I have illustrated my circuit breaker, generally indicated at II, as provided with a manually operable trip knob or handle 4|, upward movement of which causes tripping of contacts. used? circuit breaker it. A circuit breaker provided with a manually operable handle for tripping purposes when moved upwardly is disclosed in United States Letters Patent to W. A. Atwood, 1,589,924, granted June 22, 1926, and assigned to the assignee of the present application.

In order to cause tripping of circuit breaker It prior to withdrawal of removable unit i2 and disengagement of primary disconnecting contacts I! and It, I provide a suitable interlocking means which cooperates with trip knob 40 and the looking device for removable unit I: described above. I have illustrated this interlocking means as comprising a vertically movable pin 4! mounted directly below knob 40 so as to be movable in suitable openings provided in bracket members 42 and 48 supported on removable unit I: by channel shaped member 2|. The upper part of pin Ii adjacent knob 40 is provided with an enlargement 44 adjacent knob movement thereof. The lower end of pin ll extends closely adjacent lever ll when pin ll is inserted in one of the openings It, 31, or I8 of stop member 39. A suitable stop member 45 associated with pin 4| and cooperating with bracket 42 limits the downward movement of pin 4| so that the lower end thereof extends somewhat below lever II. Referring to Figs. 5 and 6, it will be observed that pin ll prevents movement of lever II in a counter-clockwise direction to allow withdrawal of pin it from opening It in stop ll. Therefore, removable unit I: cannot be withdrawn with respect to intermediate unit ll so as to cause disengagement of primary disconnecting contacts II and it unless pin 4! is moved upwardly to free lever 3|. This upward movement of pin ll will cause upward movement of knob 4| and consequent tripping of the circuit breaker. Furthermore, as long as lever II is moved to a. position so that pin 33 is withdrawn from one of the openings ll, 31, or so in stop ll, pin II will rest on lever II in its raised position, holding trip knob ll upwardly to insure that circuit breaker It remains in The operation of the switchgear embodying my invention will be understood by those skilled in the art in view of the detailed description given above. Due to the provision of intermediate unit 40 to facilitate manual my invention and I. therefore,

theopenposition. as

H, the primary disconnecting contacts II and ll may be adjusted in the factory so as to properly engage and disengage when removable unit I! is moved in drawer fashion on ball bearings 2|. Thereafter, when intermediate unit II is secured into housing II, no further diilicultiee will be 75.

contests is concerned or rack-on mechanism if one provided since the latter may also be justed the factory with the removable unit it and the intermediate unit it removed from housing it. Other parts of the intermediate unit which re- .adjustment with respect to the removable be adjusted at this time. Removable unit is slidably mounted on ball bearings supported by intermediate unit it and is held 81, When pin II engages cuit breaker is in the primary disconnecting disconnecting devices disenare also interrupted.

It will be understood by those skilled in the art that removable units I! may be readily interchanged in so far as circuit breakers of similar capacity are concerned. By this arrangement, therefore, one type of intermediate unit and metal enclosure may be used interchangeably with removable units including circuit breakers of similar interrupting capacity.

While I have shown and described a particular embodiment of my invention, I do not desire my invention to be limited to the construction shown and described for it will, of course, be obvious to those skilled in the art that changes and modiflcations may be made without departing from aim in the appended claims to cover all such changes and modiiications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A switchgear of the type including a stationary housing, a separate intermediate unit aranged to be supported in said housing, a movable structure including a circuit breaker mounted thereon arranged to be moved horizontally in drawer fashion toward and away from said intermediate unit, primary disconnecting devices having cooperating members carried by said intermediate unit and said movable structure, said intermediate unit and removable structure being so constructed and arranged that all features of the stationary housing such as said primary disconnecting devices which require adjustment with respect to the movable structure may be adjusted rior to installation of said intermediate unit in said housing.

termediate unit arranged to be supported in said housing,'a structure, including a circuit breaker, horizontally movable on means supported by said intermediate unit, primary disconnecting devices having cooperating members carried by said intermediate unit and said movable structure, a locking device for holding said movable structure in a plurality of predetermined positions relative to said intermediate unit, and means cooperating with said locking device for causing tripping of said circuit breaker whenever relative movement between said movable structure and intermediate unit occurs.

3. In an electric switchgear, the combination comprising a stationary housing, a separate intermediate unit arranged to be supported in said housing, a movable structureincluding a circuit breaker mounted thereon arranged to be moved horizontally on means supported by said intermediate unit, a dovetailed guide for holding said movable structure in position during movement away from and toward said intermediate unit, primary disconnecting devices having cooperating members carried by said intermediate unit and said movable structure, a locking device for holding said movable structure in at least two predetermined positions relative to said intermediate unit, and means cooperating with said locking device for causing tripping of said circuit breaker when said primary disconnecting devices are being engaged or disengaged.

4. A switchgear oi the type including a stationary housing, a separate intermediate unit arranged to be supported in said housing, a horizontally movable structure arranged to be mounted on antifriction means supported by said intermediate unit and including a circuit breaker mounted thereon, primary disconnecting devices having cooperating members carried by said intermediate unit and said movable structure, said intermediate unit and said movable structure being so constructed and arranged that said primary disconnecting devices may be adiusted for proper engagement and disengagement prior to installation of said intermediate unit in said housing.

5. A switchgear of the type including a stationary housing, a separate intermediate unit arranged to be supported in said housing, a removable unit arranged to be supported for horizontal movement by said intermediate unit and including a circuit breaker mounted thereon, said circuit breaker including a vertically movable trip member, primary disconnecting devices having cooperating members carried by said intermediate unit and said removable unit, a locking device for holding said removable unit in at least two predetermined pgsitions relative to said intermediate unit, and vertically movable means cooperating with said locking device and engageable with said trip member to insure the tripped condition of said circuit breaker when said primary disconnecting devices are being engaged or disengaged.

6. In an electric switchgear, the combination comprising a stationary housing, a movable structure including a circuit breaker mounted thereon arranged to be moved horizontally into and out of said housing, a dovetailed guide for holding said movable structure in position relative to said stationary housing during movement away from and toward said stationary housing, primary disconnecting devices having cooperating members carried by said stationary housing and said movable structure, a locking device for holding said movable structure in a predetermined position relative to said stationary housing; and means cooperating with said locking device for causing tripping of said circuit breaker when said primary-disconnecting devices are being engaged or disengaged.

BERTRAM W. MAHONEY. 

